Forward sloping chair effects on spinal shape in the Hong Kong Chinese and Indian populations

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    9 Scopus citations


    Forward sloping seats are universally accepted based on their increased trunk-thigh angle during sitting. However, these seats are not preferred by some individuals due to reasons such as excessive pressure on knees, difficulties during ingress and egress, and postural fixity during sitting. Some researchers have claimed that forward sloped sitting preserves the lumbar lordosis, thereby making it more comfortable for the sitter. This claim has not been validated across all populations and, therefore, appears to have some disagreement among researchers. In this study, spinal shape during standing and sitting in forward sloping chairs is measured and quantified using a three-dimensional sonic digitizer. Twenty subjects (ten Hong Kong Chinese and ten Indian) have participated in the experiment. Fifteen points on the spine are digitized during standing and sitting in a forward-sloping seat with trunk-thigh angles of 70°, 80°, 90°, 100°, 110°, and 120°. Different measures are used to analyze and differentiate the spinal shape. The correlation between the length of spine during standing and a subject's height is low, but significant. The behavior of the spinal shape change during sitting differs between the populations as shown by the maximum lumbar and maximum thoracic deviations. The Indian subjects seem to approach the standing curvatures in the thoracic region during 30°forward sloping sitting. The Hong Kong Chinese subjects, on the other hand, do not show any resemblance to the standing curvatures during forward sloping sitting. One possible reason could be the differences in arch angle between the two populations. The variations in spinal shape among subjects appear to be similar within a population.Relevance to industryForward sloping seats may not be appropriate for all populations since changes in the spinal shape differ between populations. The arch angle may be an indicator and possibly a predictor of the appropriateness of forward sloping seats for different populations, if spinal shape is related to sitter discomfort. Copyright (C) 1999 Elsevier Science B.V.

    Original languageBritish English
    Pages (from-to)9-21
    Number of pages13
    JournalInternational Journal of Industrial Ergonomics
    Issue number1-2
    StatePublished - 1 Jan 1999


    • Forward sloping seats
    • Lumbar curvature
    • Sitting
    • Spinal curvature
    • Spine


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